ABSTRACT
BACKGROUND
Venous thrombosis is a common disease with frequent complications, such as pulmonary embolism in the acute period, and post-thrombotic syndrome in the later period. Risk factors for venous thrombosis have been explained by Virchow’s triad of endothelial injury, hypercoagulability and venous stasis. May-Thurner's syndrome is an anatomic cause of venous stasis. It involves the formation of hyperplasia of the venous intima in the left common iliacal vein due to chronic pulsations of the right iliac artery that runs over the vein, and the lumbar vertebra that lies under the vein. The intraluminal thickening causes a chronic venous disorder, which can lead to venous hypertension. The exact incidence of the syndrome is unknown and is likely to be underestimated, and the syndrome as a risk factor in venous thrombosis is poorly defined.
Post-thrombotic syndrome is a common late complication of venous thrombosis. Its pathophysiology is not fully understood, but probably involves the interplay between damaged venous valves, residual venous thrombosis or obstruction, and impaired microcirculation due to consecutive persistent venous hypertension. The risk factors for the development of post-thrombotic syndrome are numerous and some are poorly researched. Post-thrombotic syndrome may severely diminish quality of life.
The purpose of the study was to assess the importance of MTS in developing acute left leg deep venous thrombosis and consecutive development of post-thrombotic syndrome.
HYPOTHESIS
May-Thurner syndrome is an important risk factor for the occurrence of deep left-sided venous thrombosis in young women.
May-Thurner syndrome is a risk factor for the development of post-thrombotic syndrome in young women with a history of proximal left-sided deep venous thrombosis.
METHODS
Influence of May-Thurner syndrome on developing deep venous thrombosis
The first part was a case-control study where 68 female patients, aged between 18 and 45 years, treated due to left-sided proximal venous thrombosis in the past, were compared with the same age group patients without thrombosis (n=60). Magnetic resonance venography was performed to confirm May-Thurner syndrome.
Influence of May-Thurner syndrome on developing post-thrombotic syndrome
Patients with a history of left leg proximal deep venous thrombosis (n=68) were segregated according to the presence or absence of post-thrombotic syndrome according to Villalta score. Patients who developed post-thrombotic syndrome (n=25) were compared with known risk factors for the development of the post-thrombotic syndrome (deep or superficial venous insufficiency, residual thrombus) and the presence of May-Thurner syndrome with a group of patients, who did not develop a post-thrombotic syndrome (n=43).
RESULTS
May-Thurner syndrome as a risk factor for deep venous thrombosis
May-Thurner syndrome was present in 53 % patients with venous thrombosis and in 25 % patients without thrombosis. May-Thurner syndrome was significantly related to venous thrombosis risk (odds ratio (OR) 3,32, 95 % confidence interval (CI) 1,56 – 6,94, P = 0,001). Other risk factors - pregnancy (OR 12,59), use of oral contraceptives and hormonal replacement therapy (OR 3,12), thrombophilia (OR 11,31), obesity (body mass index above 30 kg/m2, OR 12,07), positive family history of venous thromboembolism and other factors were also statistically related to venous thrombosis risk.
May-Thurner syndrome as a risk factor for post-thrombotic syndrome
Out of 68 patients, 25 developed post-thrombotic syndrome (36,8 %). May-Thurner syndrome was not linked to development of post-thrombotic syndrome (risk ratio (RR) 1,13, P = 0,80). Deep and superficial venous insufficiency were statistically significant related to post-thrombotic syndrome (RR 1,95; P = 0,01 and RR 4,27; P=0,0001, respectively), while residual thrombosis showed only trend (RR 1,65; P = 0,07).
CONCLUSION
We confirmed that May-Thurner syndrome is an important risk factor for the occurrence of deep venous thrombosis in young women.
We did not confirm that May-Thurner is an important risk factor for post-thrombotic syndrome development in young women with a history of proximal left leg venous thrombosis.
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